Sirama chrishna gives the example of a of the cobra and the water snake. If it is taught by lightened master, of course, to a prepared student, then enlightenment is guaranteed. Even if you don't want to, you'll become enlightened. There is no other way. You have no escape.
Swami Sarvapriyananda teaches the Katha Upanishad, which is one of the most popular Upanishads. The scripture concerns the story of a young man who goes to the house of death to find out what happens after death. The reply describes the nature of reality and the meaning of life.